1. Field of the Invention
The present invention relates to a surgical stapling and cutting instrument adapted for use in the diagnosis and therapy of pathologies treated by stapled resection. More particularly, the invention relates to a firing mechanism for utilization in conjunction with the cartridge module of a surgical stapling and cutting instrument.
2. Description of the Prior Art
Surgical stapling and cutting instruments are commonly utilized in the diagnosis and treatment of pathologies treated by stapled resection. Surgical stapling and cutting instruments provide a mechanism to extend the transluminal exploitation of mechanical suturing devices introduced via the anal canal, mouth, stomach and service accesses. Although surgical stapling and cutting instruments are most commonly utilized with rectal pathologies, surgical stapling and cutting instruments may be used in a variety of environments.
Over time, surgical stapling and cutting instruments have been developed. These instruments generally include a support frame, an anvil attached to the support frame and a cartridge housing carrying a plurality of staples. The instruments also include a driver within the cartridge housing which pushes all of the staples out simultaneously into the anvil to form the staples into a generally B-shape, suturing tissue together. In addition, these instruments include approximation mechanisms for moving the cartridge housing from a spaced position from the anvil to accept tissue therebetween to a closed position where the tissue is clamped between the anvil and the cartridge housing. Finally, the instruments include a firing mechanism for moving the driver forward to form the staples against the anvil.
In order to facilitate reuse of the surgical stapling and cutting instruments, many of these devices are provided with cartridge modules. The cartridge modules provide for the ready replacement of staples and/or blades without disposing of the entire surgical stapling and cutting instrument.
In accordance with prior art instruments, the cartridge housing for surgical stapling and cutting instruments contains a knife for transecting tissue. The knife resides in the cartridge housing and a fresh knife is therefore, provided for use in conjunction with each firing. After completion of the firing stroke, and upon release of the firing trigger, it is desirable to have the knife retract automatically into the housing for the cartridge housing. Furthermore, it is desirable for the knife to be positively connected to the firing mechanism so that if a knife becomes jammed in the tissue or in the cutting washer, the user can free it by rotating the firing trigger (in the direction opposite the firing).
As such, a cartridge housing offering a retracted knife and a knife directly linked to the firing mechanism are desired. The present invention provides such a knife structure.